Positive displacement pumps commonly include a pressure relief device in the event of extreme overpressurization within the pump. Excess pressure may be released through this device, thereby preventing catastrophic valve of the pump. Even in the absence of extreme overpressurization, however, pumps may still be damaged by overheating if the discharge flow is partially or fully blocked. In such case, water or other pumped fluids heat up within the pump and may flash into the vapor phase. In this situation, the pump can be heavily damaged due to thermal expansion of the parts during this overheating.
In order to eliminate, or at least reduce pump damage resulting from such overheating incidents, it would be desirable to provide a pump design in which both pump overheating and pump overpressurization may be separately and independently relieved.